1. Field of Invention
The present invention relates to novel mixtures of phosphite antioxidants for polymeric resin compositions. It also relates to stabilized resin compositions and stabilizer concentrates comprising said novel liquid mixtures of phosphite antioxidants.
2. Description of Related Art
Organic phosphites (aka phosphorous acid esters) are known in the art as secondary antioxidants for polyolefins, polyvinyl chloride, and elastomers. Examples of such known phosphites are given in H. Zweifel (Ed) Plastics Additives Handbook, 5th edition, Hanser Publishers, Munich 2000. One of the most widely used organic phosphites is trisnonylphenyl phosphite (TNPP), which is a liquid at room temperature. There is, however, a need to replace TNPP owing to the alleged estrogenicity of nonylphenol. Furthermore, as TNPP is a liquid at ambient conditions, there is a need to replace it with a phosphite that is also a liquid at ambient conditions.
Phosphite stabilizer blends, both liquid and solid, are known in the art.
U.S. Pat. No. 3,948,801 discloses stabilizing compositions comprising at least one triaryl phosphite, trialkyl phosphite or mixtures thereof and at least one modified lignin, the weight ratio of the phosphite to modified lignin being from 97/3 to 10/90. The modified lignins are produced by heat treating lignins in the presence of a nucleophile, such that a portion of the original guaiacyl structures are converted to catechols via a demethylation reaction. Elastomers are said to be protected against atmospheric degradation by the addition thereto of 0.01 to 5.0 parts by weight per 100 parts of elastomer of the stabilizing composition.
U.S. Published Patent Application No. 2003/0001136 and U.S. Pat. No. 6,824,711 disclose a liquid polymer additive composition comprising at least one phosphite ester selected from the group consisting of aryl phosphites, alkyl phosphites, aryl/alkyl phosphites, bisphenol-A phosphites, dialkylene glycol phosphites and polydialkylene glycol phosphites, pentaerythritol phosphites, p-cumyl phenol phosphites and blends thereof and approximately from 50 to 800 ppm inclusive of zinc per 100 parts resin. The stabilizer is used as either a complete or a partial replacement of toxic-metal containing antioxidant stabilizer additives.
U.S. Published Patent Application No. 2004/0183054 discloses liquid polymer additive compositions comprising blends of phosphite esters selected from the group consisting of aryl phosphites, alkyl phosphites, aryl/alkyl phosphites, bisphenol-A phosphites, dialkylene glycol phosphites and polydialkylene glycol phosphites, pentaerythritol phosphites, p-cumyl phenol phosphites with from 50 to 800 ppm inclusive of zinc per 100 parts resin. The stabilizer is used as either a complete or a partial replacement of toxic-metal containing antioxidant stabilizer additives.
U.S. Published Patent Application No. 2007/0021537 discloses a process for stabilizing polyolefin compositions against the deleterious effects of melt processing, heat aging and exposure to combustion products of natural gas, which process comprises incorporating or applying to a polyolefin an effective stabilizing amount of a tris-(mono-alkyl)phenyl phosphite ester of the formula I,
or a mixture of phosphite esters of formula I, where each R is the same or different and is straight or branched chain alkyl of from 1 to 8 carbon atoms, and where said phosphite ester or phosphite ester mixture is in the liquid state at 25° C. and 1 atm of pressure. Also disclosed is a stabilized composition comprising polyolefin and a present phosphite ester or phosphite ester mixture as well as certain mixtures of tris-(mono-alkyl)phenyl phosphite. These liquid phosphite ester stabilizers are said to be especially compatible with low density polyethylene.
CA 2,464,551 discloses solid mixtures of individually solid phosphite components for the phenol-free stabilization of polyethylene film.
CZ 280072 discloses mixtures of phosphites and phosphonites as stabilizers for propylene polymers.
DE 90-4,001,397 discloses phosphonite and phosphite esters as heat stabilizers for polymers.
JP 05202236 discloses blends comprising phosphites and phosphonites said to be useful in the production of heat-resistant polyolefin compositions.
JP 59030842 discloses solid phosphite blends comprising solid phosphites said to be useful in the stabilization of polyolefin compositions.
RO 112871 discloses compounds of the formula (RR1R2C6H2O)3P wherein (R, R1, R2═CMe2Ph; or R═H, R1, R2═CMe2Ph; or R═R1═H, R2═CMe2Ph) as a mixture of triphosphites of phenol and mono-, di- and triarylalkylated phenols that consist of a mobile yellow liquid containing 4±0.3% P and 0.5% Cl and having an index of refraction of 1.5992 and d 1.1400 g/cm3, said to be useful as stabilizers for polymers and elastomers (no data). The mixture is prepd. by esterification of PCl3 with a mixture of phenol and mono-, di- and triarylalkylated phenols having a median molecular weight of 300 in a molar ratio of arylalkyl phenols to phenol of 1:1-1.5 and arylalkyl phenol+phenol to PCl3 of 1:0.3-0.4 with no solvent or catalyst under anhydrous conditions with agitation at 25-40° for 0.5-1.5 hours, then gradually raising the temperature to 90-150°, maintaining the temperature at 150-180° or 2-6 hours, removing the HCl formed in the reaction by bubbling nitrogen through the reaction mass at 150-180° for 2-5 hours, and then removing the unreacted starting materials by distillation in an inert nitrogen atmosphere at 10 mm Hg at 175°. In the example given, 989 grams of a mixture of (1-methyl-1-phenylethyl)phenols produced by alkylation of phenol with α-methylstyrene and 475 grams of phenol are melted with stirring at 25° and 383 grams of PCl3 are added dropwise over 1 hour, whereupon the mixture is gradually heated to 90°, held 1 hour at 90°, then heated to 150° and held there for 5 hours, after which the HCl formed is blown out by bubbling nitrogen through the mixture at 150° for 5 hours, after which the unreacted phenols are removed by distillation under nitrogen at 175° and 10 mm Hg pressure to give 1460 grams of a product mixture that is a yellow liquid containing 4.14% P and 0.5% Cl, with an index of refraction of 1.5992 and d 1.1400 g/cm3, which contains tri-phenyl phosphite and the triphosphites of 2-(α,α-dimethylbenzyl)phenol, 4-(α,α-dimethylbenzyl)phenol, 2,6-bis(α,α-dimethylbenzyl)phenol and 2,4,6-tris(α,α-dimethylbenzyl)phenol.
WO 02070625 discloses liquid phosphite mixtures as additive compositions.
WO 2001/062832 discloses the addition of stabilizer additives to polymer particles for rotational molding.
WO 2001062833 discloses mixtures of organic phosphites and phosphonites useful in the addition of stabilizer additives for polymer particles for rotational molding.
WO 9303092 discloses the use of solid mixtures of individually solid phosphite components as heat-resistant polyester-polycarbonate molding compositions.
The disclosures of the foregoing are incorporated herein by reference in their entirety.